Fuji Pigment Co. Ltd. announced today that it has developed a new type of aluminum-air (Al-air) battery rechargeable by refilling salty or normal water and having a modified structure which ensures longer battery lifetime. The aluminum-air battery has a theoretical specific energy level of 8,100 Wh/kg and has the second largest capacity among various types of potential secondary batteries. Theoretical specific energy of a commercialized lithium-ion battery is 120-200 Wh/kg. Therefore, the aluminum-air battery possesses theoretical capacity more than 40 times as large as that of a lithium-ion battery.
Due to fossil fuel depletion and the air pollution arising from its combustion, there is urgent demand for renewable, clean fuel alternatives for our future energy supply. Although commercialized rechargeable lithium-ion batteries are widely used in mobile phones, laptop computers, and similar electronic devices, their energy density is still insufficient to permit their use in electric vehicles at an industrial level with economical cost. The highest energy storage technologies faced by recent researchers are the metal-air batteries.
Several metal-air batteries such as lithium, iron, aluminum, magnesium and zinc-air, etc. have been investigated due to their promising energy densities. Among them, aluminum is an abundant, attractive anode material for energy storage and conversion because of its high specific capacity, highly negative standard electrode potential. In addition, aluminum is the most recycled metal in the world and is economically cheap.
A major barrier to commercialization has been the high corrosion rate of aluminum during the electrochemical process. In addition, byproducts such as Al2O3 and Al(OH)3 accumulate at electrodes, hindering further battery reaction.
Regarding this obstacle, Dr. Ryohei Mori at Fuji Pigment Co. Ltd. has invented the new type of aluminum-air battery. He has modified the aluminum-air battery structure by placing ceramic and carbonaceous materials between aqueous electrolyte and electrodes as an internal layer. Owing to this modified structure, anode corrosion and byproduct accumulation were suppressed, which resulted in longer battery lifetime.
The newly invented aluminum-air battery can work just by refilling salty water or normal water once in a while. Aluminum is an abundant, cheap and safe material which can be applied for metal-air batteries. Therefore, battery prices can be cheap. The new battery can be manufactured and work in an ambient atmosphere because it is stable in ambient air conditions. Moreover, there is no need to worry about explosion or flammability like a lithium-ion battery. All materials (electrode, electrolyte) are safe and cheap, and can be made very easily even in the house kitchen.
Theoretically, the aluminum-air battery has the second largest capacity next to a lithium-air battery which is the strongest secondary battery. (Lithium-ion battery: 120-200 Wh/kg, aluminum-air battery: 8,100Wh/kg, lithium-air battery: 11,400 Wh/kg). The aluminum-air battery has theoretical capacity more than 40 times that of a lithium-ion battery.
Basic battery properties include: 0.7-0.8 V, 400-800 mA/cell (10 cm x 10 cm), 4-8 mA/cm2; Battery works for minimum 14 days by refilling salty water or normal water occasionally. Also, we can modify the battery at the request of customers (For example: 10.0-12.0 V, 4.0-8.0 A or even stronger battery). Fuji Pigment Co. Ltd. is constantly improving the battery performance and planning to commercialize this new type of aluminum-air battery in the market by Spring 2015.
